Beam advice

Page 1 of 3  
I need to place a beam to support a ceiling (and roof above that). The span is 14 feet. Supported only on the ends. I'm thinking of 3 2x12's with a half inch of plywood between each. Is this overkill, not enough, or just right? I don't really want anymore beam than necessary, but also don't want it sagging 5 years from now.
thanks!
--
Steve Barker
Stilwell, KS
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Steve Barker LT wrote:

Frankly I would have an engineer take a look at what you are doing. You really have not provided enough information for someone to make an intelligent recommendation. I recommend the professional because they would look at the actual situation, You might unintentionally leave out some important fact in describing it that could be important.
--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
uhhh, nobody in their right mind would HAZard a guess, or try this without Pro advise
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Depends on the kind of wood and the load and its distribution.

Like, what's the load on the beam? With bending moment M = WL/8 in-lb and a total uniform load W in pounds and L = 14x12" and S = M/f = bd^2/6 in^3 and f = 1000 psi and d = 11.25" and b = 5" (3x1.5+0.5, if half the plywood grain runs lengthwise), W = 8bd^2f/(6L) = 8x5x11.25^2x1000/(6x14x12) = 5022 pounds. You might make it stronger by substituting some metal for plywood.
Nick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
An engineer is your only safe answer, as Meehan says. I would not depend on a carpenter or contractor to "design" the structural system. You need to look at the load path all the way to the ground. If you have a building department, they will want documentation. TB
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
An engineer is your only safe answer, as Meehan says. I would not depend on a carpenter or contractor to "design" the structural system. You need to look at the load path all the way to the ground. If you have a building department, they will want documentation. TB
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
try your local lumberyard. usually manufacturers of engineered wood beams have engineers on staff who will size beams provided you are buying their product. LVL's would likely be the way to go here, anyway.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sounds very strong, but what is the load? Anyone here would be guessing since none of us know the total load to support.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for the many replies. I'm sorry I didn't supply enough info. It's an old house that we're fixing up for our own use. An engineer is out of the question. What I failed to mention is that this is a kitchen ceiling where the house was added on to many years ago. The kitchen is 14x20 and the ceiling joists run across the 14. What they did is basically remove the entire end wall (the original outside wall) and left only 2 rough cut 2x4's on either side of a brick chimney holding what ever load there is there. There is a picture at this link:
http://www.barkerranch.net/images/DSCN8772.jpg We do not want this mini wall and chimney in the middle of our kitchen. None of the wood members is tied to the chimney in any manner, so I figured if four 2x4's can hold it for 50 years or so, then what I propose should do the job.
--
Steve Barker
Stilwell, KS
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Steve Barker LT wrote:

I bet you don't have a building permit either since engineer is out of question. And no house insurance either....., LOL!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You are correct. No permit. I'm not building, I'm remodeling. No permit required to do what I please in my own house. Thanks for your useless reply. And BTW, yes the house is insured.
--
Steve Barker


"Tony Hwang" < snipped-for-privacy@shaw.ca> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Not true, at least anywhere in the world that I know about. I have no idea where you live, but you should *really* look at your government's regulations covering your situation. Where I live, permits are required for all structural, plumbing, HVAC, or electrical work done on (or in) my property.

Not if it falls down or is damaged due to work done without a permit. As soon as they discover work done without a permit, your insurance company will walk away.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Steve Barker LT wrote:

While there may be places in the civilized world where this kind of worm might not require a permit, most areas would require a permit. Don't be too sure about your insurance. Many insurance policies will not cover you if you did not have a permit or did not follow proper building procedures and in this case it calls for an engineer.

--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Steve Barker LT wrote:

Steve, if you want people to be a cheering section for you, well, asking structural questions on a construction newsgroup is not the way to go, particularly if you're not prepared to listen. You have not received a single useless reply yet.
As far as it being your house - no mortgage? The mortgage holder would be extremely upset to find out that you've made major structural modifications without pulling a permit. But even with no mortgage, you should be concerned as least as much as a bank would about not cutting corners on your own home.
I took the opportunity to cross post this reply. Since you've asked this question on both groups without crossposting (cross posting is not always a bad thing - it's bad only when it's to non-related groups), you are not allowing people to see the replies you've received and given. Partial information won't help your cause.
Remodeling _is_ building. If you modify the structure of your house you are required to pull a permit. Other factors will trigger the need for a permit, but a structural modification always requires a permit.
If you were in an area that didn't require permits - which, from your reply, you're not - you'd still be foolish to skip out on an engineer's review. Your picture shows more information, but still lacks critical information. Which way does the ceiling framing run? What are the required design loads? Are you in an earthquake or high wind zone? I could keep asking questions, but hopefully you've caught my drift. Only someone who has seen your house, inspected the current situation, and is familiar with you local code and area can design you a solution.
Beginners often mistake the strength of the beam as being the only factor in removing a wall. It's not - not by a long shot. The bearing area of the supports, designing connections to transmit loads other than gravity, adequacy of foundation supports, etc., are all critical. Simply picking a beam that can support a specific load is just a start.
You may have overestimated the cost and underestimated the value of an engineer in you situation? Have you called around to get an idea of the cost?
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Errr Steve? Rico is exactly correct and for some reason is showing you polite consideration... you do not deserve ..by a long shot.
Will you pay attention to Rico and thank him for his superb and accurate advice on these issues..... or will you just demonstrate your combination of ignorance and abuse.
ah yes... the latter. Impressive.
Phil Scott

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You are scaring me more now. If you remove(d) an outside bearing wall, it is not just a matter of carrying the vertical load. Almost a bigger issue is allowing the ridge to sag due to spreading of the outside walls. Perhaps your efforts should be being spent carrying the ridge. How were you planning to maintain the integrity of the roof rafter/ceiling joist/top plate connection? Has the roof load been changed by extending new roof rafters to the new outside wall? ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Did the 2x4s hold it because the were the correct strength or because of luck? Just because it survived doesn't mean it was properly designed.

Could you highlight the 2x4s you're talking about? That ceiling is hiding a lot of detail that would be pertinent.
You should contact a professional for interior or exterior structural changes. That _will_ be required unless you live in some far corner of a third world country.
Mike
PS - Ignore Nick, his posting is nonsense as usual.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You doubt it will hold up a 5022 lb uniform load? Seems conservative, IMO. Concerned about torsional longitudinal stability again? How many pounds would you estimate Steve's beam would support?
My PE friend says Unistrut has several failure modes. It's stronger with the open side down, supporting a hanging load. Nuts to hold the sides together might help in that case. Short lengths with the open side up have a local buckling mode, with the upper edges developing waviness. I wonder how to predict that.
Nick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@ece.villanova.edu wrote:

I'm thinking of a number, Nick. What's your estimate of what that number is? That is _exactly_ what you're asking. There are too many missing variables to make anything more than a wild assed guess. Precise calculations, or even yours, will not offset the missing information.

My PE friend... Please state for the record that you are not a civil engineer and have no business pretending you are one. Consider it a public service.
What does Unistrut have to do with the topic of this thread? You're not obsessing again, are you?
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

And your estimate is...?

Nonsense :-)
Nick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.